In the emission of photo-electrons, the number of photo-electrons emitted per unit time depends upon the

Options

A. Energy of incident radiations
B. Frequency of incident radiations
C. Intensity of incident radiations
D. None of the above

Answer

To determine the factors that influence the number of photoelectrons emitted per unit time during the photoelectric effect, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Photoelectric Effect**:
- The photoelectric effect occurs when light (photons) strikes a metal surface and causes the emission of electrons. The energy of the incoming photons must be sufficient to overcome the work function of the metal for electrons to be emitted.

2. **Role of Photon Energy**:
- Each photon has a specific energy given by the equation \( E = h \nu \), where \( h \) is Planck's constant and \( \nu \) is the frequency of the light.
- If the energy of the photons is increased (by increasing the frequency), it can excite electrons, but each photon can only emit one electron. Therefore, increasing the energy of individual photons does not increase the number of emitted electrons per unit time.

3. **Role of Intensity of Light**:
- The intensity of light is related to the number of photons striking the surface per unit time. Higher intensity means more photons are available to interact with the electrons in the metal.
- If the intensity of the incident light increases, the number of photons hitting the metal surface increases. This results in a higher probability of electrons being emitted because more photons can interact with more electrons.

4. **Conclusion**:
- The number of photoelectrons emitted per unit time depends primarily on the intensity of the incident light. Therefore, the correct answer is that it depends on the intensity of the radiation.

### Final Answer:
The number of photoelectrons emitted per unit time depends upon the intensity of the incident radiation.